Electron discharge apparatus



Aug. 30, 1949. R w, N s 2,480,122

ELECTRON DISCHARGE A PARATUS Filed Sept. 10, 1947 2 Sheets-Sheet l 5/ 52/3 I I v INVENTOR. I62 16/ Richard W Dumb/s Attorney Aug 30,1949. w, N s2,480,122

ELECTRON DISCHARGE APPARATUS Filed Sept. 10, 1947 2 Sheets-Sheet 2uvvszvroa. Richard W Danie/s Affomay Patented Aug. 30, 1949 UNITEDSTATES PATENT OFFICE '(Granted under the act of March 3, 1883, asamended April 30, 1928; 370 0. G. 757) 8 Claims.

This invention relates to electron discharge apparatus, particularlysuch apparatus as is used for producing a brilliant flash of actiniclight for photographic purposes. More particularly, this inventionrelates to a holder in which an electron discharge device capable ofproducing a flash of photographic light may be mounted.

It is an object of this invention to provide means for improving thetiming control over a flash of actinic light.

It is another object of this invention to provide a holder for anelectron discharge device having an adjustable member whereby the firingof the device may be regulated for optimum performance.

It is still another object of this invention to provide a holder for anelectron discharge device having adjustable means whereby the holder mayaccept devices of difierent sizes and shapes with equal functionaleffectiveness.

In the following description there will be described photographicapparatus for producing a brilliant flash of actinic light. An importantelement of this apparatus is the electron discharge device and holder ofthe instant invention.

Referring to the drawing, Fig. l is a schematic diagram of an electriccontrol circuit for energizing electron discharge apparatus to produce aflash of light. v

Fig. 2 is a face view of the electron discharge apparatus which producesthe flash of photographic light.

Fig. 3 is a face view of a camera showing a tripping means whereby theflash of actinic light may be synchronized with the opening of thecamera shutter.

Fig. 4 is a fragmentary top view, partially sectioned, of the electrondischarge apparatus of Fig. 2.

Fig. 5 is a partially sectioned view of the apparatus of Fig. 4, takenalong the oblique line 3-5 in Fig. 4.

Fig. 6 is an enlarged face view of the camera shown in Fig. 3.

The energizing circuit In Fig. 1, the plug adapted to be connected to asource of 110 volt alternate current power, is connected to the primarywinding l2 of a transformer l3 through a switch H. A high voltagesecondary winding l5 of the transformer I3 is grounded at one end asshown at l6, and is connected at the other end to the plate of 9.rectifler tube H. The rectifier cathode is heated in conventional mannerby energy from a low voltage secondary winding i8 013 the transformerl3. With the rectifier tube thus connected, the cathode conductor l9 hasapplied thereto a relatively high uni-directional potential.

Conductor I9 is connected to a conductor 2| through a bridging contact,22 of a relay 23. Between conductor 2| and the ground It is connected astorage capacitor 24. Thus whenever transformer l3 and relay 23 areenergized, capacitor 24 will be connected to, and charged by, a highvoltage direct current source in the form of rectifier l1.

Capacitors 25 and 26 may be successively paralleled with capacitor 24through a multiterminal switch 21, having a rotatable bridging member28. In the particular position shown for bridging member 28, in Fig. 1,only capacitor 25 is connected to conductor 2| so that th totalcapacitance charged from the high voltage direct current line is the sumof capacitors 24 and 25. It will be manifest from the drawing that allthree capacitors may be paralleled by rotating the bridging member 28one position counter-clockwise; while by rotating member 28 one positionclockwise, only capacitor 24 will be connected to conductor 2|.

The relay 23 is employed in the circuit of Fig. 1 to insure that thehigh voltage conductor |'9 will not be connected to the capacitors 2426until the apparatus has been operating long enough to insure adequateoperating temperature in the cathode of rectifier l1. The necessary timedelay is provided by a small motor 3| connected, through gears 32, to aconducting disk 33. One terminal of motor 3| is connected permanentlythrough a conductor 34 to one side of the plug The other side of themotor is connected to the other side of the alternating current sourcethrough a conductor 35 and through the relay contact 22. Thus as soon asthe switch I4 is closed to start heating of the cathode of rectifier H,the motor 3| is also energized to institute rotation of the disk 33. Insliding contact with the disk 33 is a brush 35 connected to theconductor 34. Disk 33 carries a contact 31 which bears against astationary contact 38 whenever the disk has been rotated a predetermineddistance. Contact 38 is connected to one side of the coil 39 of relay23, the other side of which is connected to the alternating currentconductor 35. Thus, a predetermined time after closing of the switch i4,when the motor 3| has rotated the disk 33 so as to move the contact 31into engagement with the contact 38, the relay coil 39 is energized,thereby lifting the armature 4| and causing contact 22 to complete thecircuit tor the capacitors 24-28. Deenergization of the motor 2|, by thelifting of contact 22, would normally cause the disk 22 to snap backunder the impulse oi a torque biasing spring 42; but this is preventedby an interlock member 43, attached to the armature 4| which physicallyengages the contact 31 and holds it against the contact 30. Theenergizing circuit for coil 39 through contacts 31-32 is thus heldclosed by virtue of the raised position of armature 4|. Under thiscondition the capacitors 24-20 will be charged from rectifier II, thevoltage of this charge appearing between conductor 4 connected to groundI6, and the high voltage direct current conductor 2|. The quantity ofthe charge depends on the number of capacitors 24-28 across the line,which in turn depends on the position of the switch 21.

An indicator light connected across the primary winding I2, shows whenthe apparatus has been energized by the closing of switch It. A highvoltage indicator light 62 is also placed across the primary winding I2through an auxiliary contact 53 carried by the armature 4| of relay 23.Light 52 indicates that the delay time has passed, and that the highvoltage from rectifier II has been applied to the conductor 2|, and tothe capacitors 24-25.

In order that a high voltage will not remain on the conductor 2| whenthe apparatus is not in use, means must be provided for discharging thecapacitors 24-26. To this end the conductor 2| is grounded through aresistor 55 and a relay 56, the coil of which is energized whenever theswitch I I is closed, thereby opening the grounding circuit.

The apparatus of this invention also employs a high voltage alternatingcurrent, which is derived through a transformer 6|, the primary winding62 of which is connected in parallel with the primary winding I2 througha plug 63, which is in turn connected to a switch on the camera of Fig.3 (to be described later). One side of the secondary winding 64 of thetransformer 6| is grounded through a conductor 65, and the other side isconnected to a conductor 60. A plug 61 is provided to which the groundconductor 44 and the high voltage direct current conductor 2| areconnected, and also to which the ground conductor 65 and the highvoltage alternating current conductor 66 are connected.

The circuit of Fig. 1 thus makes available for the electron dischargeapparatus of Fig. 2, a direct current potential between conductors I"and 2|, as stored on the capacitors 24-26. It also makes available ahigh voltage alternating current between the conductors 55 and 66. Thislatter voltage. however, does not appear until the conductors of theplug 03 have been bridged by operation of the switch on the camera shownin Fig. 3.

The camera In Fig. 3 there is shown the face of a camera ii having aconventional lens assembly I2, which includes a shutter setting lever I3and a shutter release lever l4. Pivoted on the face of the camera II bya pin i5 is a cam arm it having a knob TI which bears against aprotuberant portion of a spring contact I8. Spring contact 78 cooperateswith an opposed spring contact 19 to comprise a normally open switch,which is closed momentarily as the cam arm I6 rotates counterclockwise.The contacts 18 and I0 are connected through a plug 8| to conductors 82which may be connected'to the plug 63. In series with one of theconductors 82 is a normally open foot switch 83, which must be held downduring operation of the camera in order to complete the circuit forenergizing the primary winding 62 of the transiormer 6|.

Tripping oi the camera, which causes counterclockwise motion of thelever I3 in the conventional manner, also efiectuates, through a link84, the afore-mentioned counter-clockwise rotation 01' the cam arm 16and thereby energizes momentarily the primary winding 62. The cameratripping lever II is actuated through a solenoid 85 energized by a smallbattery 86 through a manually carried push button 81.

For optimum photographic results it is necessary that the shutteropening of the camera be precisely synchronized with respect to theclosing of the light tripping contacts I8 and 19. In order to achievethis synchronization for various makes of cameras 'II, it is desirablethat the length of the link 04 be adjustable. As shown in Fig. 6, thisis done by making the link 86 in two parts. One of these parts consistsof a female fitting 9| connected through a rod 92 to an extension arm 93firmly aflixed to the shutter setting lever 13. Into the female fitting9| is threaded the other of these parts, a male fittingjfl having ahexagon head 95, swiveled on an arm 96, the end of which is pivoted at91 to the upper end of the cam arm I6. By adjusting the fitting 94 inthe fitting 9|, the length of the link 84 may be altered to synchronizeproperly the shutter opening with the closing of contacts I8 and I9, andhence with the flash of light from the flash apparatus shown in Fi 2.

The flash lamp The flash lamp, or electron discharge apparatus, formingthe claimed subject matter of this invention is illustrated in Figs. 2,4, and 5. Referring to Fig. 2, the apparatus includes a light reflectorMI, in front of which is mounted an electron discharge device I02. Thedischarge device |02 comprises a tubular, helical, electron dischargeenvelope I03 surrounded by a transparent cylindrical cover I. Thebottomtermination of the envelope I03 contains an electrode I05 and thetop termination likewise contains an electrode I06. The electrondischarge device I02 is of the plug-in type, being provided withparallel prongs I01, I08, and I00. The prong I01 is connected to 'anupstanding conducting post III, disposed parallel to the axis of thehelical envelope I03 just outside the convolutions thereof. A loop I I2extending internally of the helix I03 and attached to the post IIIserves to physically support one side of the envelope I03. The otherside of the envelope is similarly supported by a post I I3, connected tothe prong I09, and having a loop II'fi similar to the loop H2. The postIII is electrically connected by a wire I I5 to the electrode I05, andthe post H3 is connected by a wire II 6 to the other electrode I06.

High voltage direct current is applied to the envelope M3, for dischargetherethrough, by conductors |2I and I22, the former being connected tothe prong I01 and the latter to the prong I09 through a suitable femaleplug in the electron discharge apparatus of Fig. 2. The conductor I 2|is connected to the ground conductor M (Fig. 1), and the conductor I22is connected to the high voltage direct current conductor 2|, throughthe gig 61, as shown by the schematic dotted lines It will be seen fromthe description of the apparatus thus far that when the electrondischarge apparatus of Fig. 2 is connected to the circuit of Fig. 1through the plug 61, the switch I4 closed, and the motor 3i rotated toclose the contacts 31-30, there is applied between the electrodes I05and I06 8. high direct voltage from the charge in thecapacitors 24-26.This voltage is not of sufiicient magnitude to break its own paththrough the helical envelope I03. The capacitors 24-26 will notdischarge through the envelope I03 until an ionizing field has beenapplied thereto from the high voltage transformer H. The manner in whichthe ionizing potential is applied to the envelope I03 will now bedescribed with particular reference to Figs. 4 and 5.

As shown in Fig. 5, the electron discharge apparatus comprisesessentially a holder I3I and the electron discharge device I02. Theholder I3I includes a base I32 having hand grip slots I33 therein. Thereflector IN is mounted on the base I52 and has a hole I34 (Fig. 2) nearthe bottom thereof, through which the electron discharge device I02passes when installed in the holder MI. The rear portion of thereflector IN is formed into a backward extending cylinder I85, which isfiexedly mounted as shown at I36 in the base I82. The inside of thecylinder I35 forms a recess for the reception of an internallytelescoped cylinder I3I, which protrudes forwardly from the cylinder I35toward the electron discharge device I02. The cylinder I3I constitutes amounting or support member for a conducting capacitor plate I38, whichis transversely secured across the forwardly extending end of thesupporting cylinder I3'i. As best seen in Fig. 4, the capacitor plateI36 is in the form of an arcuate portion of a cylinder, so that it mayflt closely to, and conform to the configuration of, the transparentcover I04 of the electron discharge device I02.

The outer cylinder I36 has a longitudinal slot Iti in the upper wallthereof, through which passes a set screw I42 threaded into a tappedhole in the mounting cylinder I3I. In this manner the capacitor plateI38 may be adjusted toward or away from the cover I04 by the telescopingof the cylinders I3I and I36, and held securely in an adjusted positionby the screw and slot arrangement I42 and III.

Cooperating electrically with the capacitor plate iii is a conductor inthe form of a third mounting post I5I, having a loop I52 which en--compasses the convolutions of the helix I03 and serves to physicallysupport the helix within the cover I04. However, unlike the posts IIIand II3, the post I5I has no conducting relation to the envelope I03similar to the electrodes I05 and I06. Instead, the post I5I togetherwith its loop I52 represents a capacitor plate which, with theconducting plate I38, establishes an electrostatic field across aportion of the helical convolutions. This field is suflicient to breakdown the resistance within the envelope I03, thereby allowing the chargeon the capacitors 24-26 to pass from the electrode I06 to the electrodeI05, and produce a brilliant dash of actinic light.

Alternating current potential from the transformer M is placed upon thecapacitor plates I5I and I30 by grounding the plate I38 through thecylinder support I3I, the cylindrical recess I35, the reflector IN, a.ground connector I6I, a conductor I62, and up to the grounded conductor65 in the circuit of Fig. 1; and by concorporated in the lens mechanismI2.

heating the other conductor 66 or the high voltage secondary winding 64to the capacity post I5I, through the plug 61, a conductor III, and theprong I08. Thus when the transformer primary winding 62 is energized bythe closing of the camera contacts I8 and I8, the high alternatingvoltage from secondary winding 64 is applied capacitively across theconvolutions of the helical Operation The operation of the photographicapparatus described above is as follows: The switch I4 is closed,thereby energizing primary winding I2, indicator light 5|, relay 56,motor 3i, and the cathode heating circuit of rectifier II. Energize.-tlon of relay 56 opens the capacitor leakage circuit including theresistor 55, and prepares the apparatus for charging of the capacitors24-26. Motor 3I rotates until the disk 33 has rotated far enough,against the force of spring' 42, to bring contact 31 into engagementwith the stationary-contact 38. This energizes relay coil 38, openingthe circuit of motor 3i, at the contact 22, and closing the circuitbetween the rectifier conductor I9 and the high voltage conductor 2iwhich supplies the capacitors 24-26. Simultaneously the auxiliarycontact 53 closes to energize the high voltage indicating light 52.

Which of the capacitors 24-26 is to be connected to the conductor 2I isdetermined by the position of the bridging member 28 of the switch 21.The briefest flash of light will be produced by the smallestcapacitance; in this case only the capacitor 24 is left in the circuit.Conversely the longest flash of light will be produced when all threecapacitors are in the circuit. In Fig. 1, switch 21 is so adjusted thatonly capacitors 24 and 25 are connected to the conductor 2|, therebypreparing the circuit for a flash of medium length.

With the energization of relay 23, the capacitors 24 and 25 are charged,and the direct voltage is applied across the electrodes I05 and I06,through the elements 2I, I22, I08, H3, 6, (I06), (I05), II5, I01,I2I,and 44.

The camera operator, having focused the camera II, rotates the shuttersetting lever I3 clockwise to the position shown in Fig. 3, where itremains by virtue of the latch mechanism in- This preparatory step,although momentarily closing contacts I8 and I9, does not energizetransformer 6I because the foot switch 83 is open. The operator thensteps on the switch 83 and presses the thumb button 81. The resultingenergization of solenoid trips the shutter release lever I4 and theshutter setting-lever I3, thereby pulling the link 84 to rotate the camarm I6 counterclockwise.

The closing of the contacts I8 and I9 momentarily applies high voltagealternating current from transformer 6I through the conductors 65 and 66to the plug 61.

This momentary voltage is applied from the plug 61 to the conductors I62and III, and thence across the capacitor plate I38 and the capacitorconductors I5I, I52. The brief electrostatic field thus placed acrossthe convolutions oi the helical envelope I03 lowers the resistance ofthe discharge path within the envelope sufllciently to allow the chargeon the capacitors 24, 25 to pass from the electrode I06 to the electrodeI05, thereby producing a brilliant flash of actinic light.

By means of apparatus constructed in accordance with the principles ofthis invention, it has been found possible to produce flashes ofphotographic light ranging from .66 microseconds to 250 microseconds,depending on the capaci-' tance placed between ground and the highvoltage direct current conductor 2 I.

It will be understood that this invention may be made and utilized inany suitable shape, size, or arrangement, depending upon the particularelectron discharge device to be accommodated, and that variousmodifications and changes may be made in this invention withoutdeparting from the spirit and scope thereof, as set forth in theappended claims.

The invention described herein may be manufactured and used by or forthe Government of the United States of America for governmental purposeswithout the payment of any royalties thereon or therefor.

What is claimed is:

1. A holder for an electron discharge device, comprising a base, acapacitor plate, a mounting member secured to said plate and extendingsubstantially normally therefrom, and means adjustably mounting saidmember on said base thereby to mount said plate in adjustable relationto an electron discharge device secured in said base.

2. A holder for an electron discharge device, comprising a base havingrecessed holding means therein, a support member movable in and out ofsaid recess, a capacitor plate secured transversely on the end of saidsupport member adapted to electrically affect an electron dischargedevice mounted in said base, and means for adjustably securing saidsupport member in said recess thereby to support said plate inadjustable relation to the discharge device.

3. A holder adapted to receive an electron discharge device, comprisinga base, a first cylinder secured to said base with the axis thereofextending out from said base, a second cylinder longitudinally slidablymounted in telescopic relation with said first cylinder, a screw andslot connection between said cylinders for adjustably securing them inpredetermined relation, and a capacitor plate secured transversely onthe end of said second cylinder adapted to be placed in adjustableposition with respect to an electron discharge device held in theholder.

4. In combination with an electron discharge envelope having electrodesfor conducting a discharge current to said envelope and a holder inwhich said envelope is mounted, a conductor mounted adjacent saidenvelope, and a conducting member disposed adjacent said envelopeforming, with saild conductor, a capacitor for applying an electrostaticfield to said envelope, and means for adjustably securing said member tosaid holder, thereby holding it in adjustable relation to said envelope.

5. In combination with an electron discharge envelope having electrodesfor conducting a discharge current to said envelope and a holder inwhich said envelope is mounted, a conductor mounted adjacent saidenvelope, and a conducting plate disposed adjacent said envelopeforming, with said conductor, a capacitor for applying an electrostaticfield to said envelope, a mounting member secured to said plate andextending away from said envelope, and means for adjustably securingsaid mounting member to said holder, thereby holding said plate inadjustable relation to said envelope.

6. An electron discharge device comprising an electron dischargeenvelope, a cover around said envelope, a capacitor conductor in theform of a plate adjustably mounted externally of said cover immediatelyadjacent thereto, the shape of said plate conforming closely to thecontour of the adjacent cover, the mounting for said plate permittingadjustability thereof toward and away from said cover and acomplementary capacitor conductor positioned to create, in conjunctionwith said plate, an electric field within said envelope.

7. Electron discharge apparatus comprising a holder, an electrondischarge envelope mounted in said holder, a substantially cylindricalcover mounted around said envelope, a capacitor conductor in the form ofa plate formed as a portion of a cylinder having a diameter slightlylarger than that of said cover, a mounting member secured to the outersurface of said plate and projecting substantially radially therefrom,means securing said member to said holder and a complementary capacitorconductor positioned to create, in conjunction with said plate, anelectric field within said envelope.

8, Electron discharge apparatus. comprising a holder, anelectrondischarge envelope mounted in said holder, a substantiallycylindrical cover mounted around said envelope, a capacitor conductor inthe form of a plate formed as a portion of a cylinder having a diameterslightly larger than that of said cover, a mounting member secured tothe outer surface of said plate and projecting substantially radiallytherefrom, means adjustably securing said member to said holder topermit adjustment of said plate toward and away from said cover and acomplementary capacitor conductor positioned to create, in conjunctionwith said plate, an electric field within said envelope.

RICHARD W. DANIELS.

REFERENCES CITED The following references are of record in the file ofthis patent:

